Dengue fever is the most important arbovirus infection found in tropical regions around the world. Dispersal of
the vector and an increase in migratory flow between countries have led to large epidemics and severe clinical outcomes,
such as dengue haemorrhagic fever and dengue shock syndrome. This study analysed the genetic variability
of the dengue virus serotype 1 (DENV-1) in Brazil with regard to the full-length structural genes C/prM/M/E among
34 strains isolated during epidemics that occurred in the country between 1994-2011. Virus phylogeny and time of divergence
were also evaluated with only the E gene of the strains isolated from 1994-2008. An analysis of amino acid
differences between these strains and the French Guiana strain (FGA/89) revealed the presence of important non-
synonymous substitutions in the amino acid sequences, including residues E297 (Met→Thr) and E338 (Ser→Leu). A
phylogenetic analysis of E proteins comparing the studied isolates and other strains selected from the GenBank database
showed that the Brazilian DENV-1 strains since 1982 belonged to genotype V. This analysis also showed that
different introductions of strains from the 1990s represented lineage replacement, with the identification of three
lineages that cluster all isolates from the Americas. An analysis of the divergence time of DENV-1 indicated that the
lineage circulating in Brazil emerged from an ancestral lineage that originated approximately 44.35 years ago.